Carbon assisted electroless gold for surface enhanced Raman scattering studies

Along with the ability to form desired architectures at the nanoscale, maximizing the enhancement factor of a Raman signal is of primary importance in a rational design of a surface enhanced Raman scattering (SERS) substrate. Here, we report how a layer of carbon on Si(100) substrate can assist and tune the formation of nanogranular gold in an electroless deposition process. It is demonstrated that Au deposited on an optimized thickness of carbon layer (similar to 90 nm) leads to a maximum enhancement factor of 10(7) with thiophenol as the probe molecule. Having characterized the substrates with AFM, XPS, and optical profilometry, their performance in SERS was tested using rhodamine 6G, hemoglobin, myoglobin, adenosine triphosphate, and adenine. In addition, the substrates are shown to be stable in the temperature range 123-433 K.